This invention relates to processes for reclaiming the inorganic reinforcing component from scrap materials including a vaporizable organic resin, such as fiberglass-reinforced compositions.
Composite materials including an organic resin reinforced with an inorganic compound, such as fiberglass-reinforced, plastic composites, etc., are used for a wide variety of applications. The production of parts from such composite materials, such as automobile parts, boat hulls and decks, tub and shower enclosures, laminated circuit boards and the like, results in a large amount of scrap as trimmings, out-of-specification production, etc. Also, scrap is generated when such parts are broken, worn out, etc. Currently, the bulk of this scrap is used as landfill or incinerated in municipal solid waste incinerators.
Recycling or salvaging the inorganic reinforcement component from such scrap materials is highly desirable because production costs can be reduced and problems associated with disposal of the scrap can be eliminated or at least minimized. Heretofore, attempts to recycle such composite materials have not been commercially feasible. One of the reasons many automobile manufacturers have not used fiberglass-reinforced plastic material more extensively is because of an inability to recycle the scrap.
Many processes for recycling fiberglass-reinforced plastic materials have focused on recovering the organic resin for heat recovery. Various processes have been used to reclaim the fiberglass fibers from mat products such as insulating materials. In one method, the mat is heated to an elevated temperature to volatize and drive off the binder which usually is about 5 to 15 wt. % of the mat. Examples of such a method are disclosed in U.S. Pat. Nos. 3,847,664, 3,852,108, 4,397,692 and 4,511,328.
U.S. Pat. No. 4,432,780 discloses a method for reclaiming chemically coated glass scrap wherein the scrap is introduced into a glass melting furnace along with an oxidizing gas, the chemical coating is oxidized and the glass fibers eventually become part of the glass melt. U.S. Pat. No. 3,448,702 discloses an incinerating method for recovering metal from printed circuit boards made from a fiberglass-epoxy laminate. The scrap is introduced into an incinerator including a forced combustion burner which impinges a high velocity stream of pressurized combustion air directly on the scrap material and scatters the metal residue and glass fibers away from the burner.
None of these patents disclose using a rotary furnace and a countercurrent flow of a purge gas for reclaiming fiberglass or other inorganic reinforcement components from scrap materials including an organic resin reinforced by the organic reinforcement component.